stator of a motor

Abstract

Disclosed is a stator of a motor. In the stator of the motor, a plurality of unit cores are connected to each other to form a stator core in a ring shape, a stator coil can be wound around each unit core, and the plurality of unit cores can be formed of materials having different magnetic flux densities from each other. Thus, it is possible to reduce iron loss by using a material having a higher magnetic flux density, and it is possible to optimize the rise in material costs by reducing the amount of use of a material having a relatively high price.

Description

Technical Field

[0001] This invention relates to a stator for a motor. Background Technology

[0002] Typically, the stator in a motor serves to generate magnetic force by magnetizing an iron core, and to produce rotational force through its interaction with the rotor. To generate this magnetic force, coils are wound around the iron core (stator core) to create a magnetic field. Therefore, to improve efficiency or output density, most stators require a structure that allows for filling more coils into the slots of the stator core.

[0003] Previously, a core in which the stator core of the motor was integrally formed (hereinafter, "integral core") was used. While this type of core has the advantage of excellent manufacturing reliability, the effective area of ​​the slots for winding the stator coil is correspondingly reduced because space needs to be ensured for the winding nozzle used for winding operations, resulting in a decrease in motor efficiency.

[0004] In view of this, it is proposed that the stator core forming the motor stator is extended and wound around the stator coil, and then the stator core is wound to form a cylindrical core (hereinafter referred to as "expanded core" or "expanded core") or the stator core is divided and wound around the stator coil, and then the stator core is assembled (hereinafter referred to as "divided core").

[0005] Patent Document 1 (WO2024-244708A1) discloses an example of a segmented iron core. In each segmented iron core disclosed in Patent Document 1, the unit iron core is formed by stacking a plurality of electrical steel plates (hereinafter, silicon steel plates).

[0006] Silicon steel sheets are mainly composed of iron (Fe) and silicon (Si), with a silicon content typically ranging from 0.5% to 6.5%. Higher silicon content results in superior electrical properties. Furthermore, due to their high electrical resistance and low losses, silicon steel sheets are primarily used in transformers, electric motors, and similar applications.

[0007] However, in the existing segmented cores described above, since each unit core is made of the same material—in other words, formed from silicon steel sheets—there are limitations in reducing iron losses. Furthermore, due to the properties of silicon steel sheets, their magnetic flux density is limited. As the tooth width of the unit core increases, the slot area decreases, resulting in a smaller diameter relative to the number of turns in the stator coil, leading to copper losses. Summary of the Invention

[0008] The purpose of this invention is to provide a motor stator that reduces iron loss and / or copper loss relative to the same outer diameter.

[0009] Another object of the present invention is to provide a stator for a motor that can reduce iron loss by optimizing the material of the stator core.

[0010] Another object of the present invention is to provide a motor stator that can reduce copper loss by increasing the slot area of ​​the stator core.

[0011] To achieve the objectives of this invention, the stator of the motor of this invention may include a stator core and a stator coil. In the stator, a plurality of unit cores may be connected to each other to form a ring. The stator coil may be wound around the plurality of said unit cores. The plurality of said unit cores may each be formed of a material with a different magnetic flux density. Therefore, iron loss can be reduced by using a material with a higher magnetic flux density, and the increase in material costs can be optimized by reducing the amount of relatively expensive materials used.

[0012] As an example, the plurality of unit cores may include a first unit core and a second unit core. The first unit core may be formed having a first magnetic flux density, and the second unit core may be formed having a second magnetic flux density higher than the first magnetic flux density. This reduces iron loss at the stator core and optimizes the reduction of material costs.

[0013] For example, the first unit core and the second unit core can be arranged alternately in the circumferential direction. This allows for improved motor efficiency and reduces the resulting increase in material costs by minimizing magnetic flux saturation at the stator core.

[0014] Alternatively, the first unit core may include a first unit yoke and a first tooth extending from the first unit yoke. The second unit core may include a second unit yoke and a second tooth extending from the second unit yoke. The width of the second tooth, defined by the width dimension between the circumferential ends of the second tooth, can be formed to be smaller than the width of the first tooth, defined by the width dimension between the circumferential ends of the first tooth. Thus, the coil diameter of the second stator coil wound around the second unit core can be increased by minimizing the amount of the relatively expensive second unit core used and increasing the slot area of ​​the second unit core.

[0015] Specifically, the first yoke distance, defined as the distance from the center of the stator core to the inner circumferential surfaces at both ends of the first unit yoke, can be configured to be the same as the second yoke distance, defined as the distance from the center of the stator core to the inner circumferential surfaces at both ends of the second unit yoke.

[0016] More specifically, the first tooth length, defined by the length from the inner circumferential surface of the first tooth to the inner circumferential surface of the first unit yoke, can be formed to be less than the second tooth length, defined by the length from the inner circumferential surface of the second tooth to the inner circumferential surface of the second unit yoke.

[0017] As another example, the first yoke end width, defined by the radial width at both ends of the first unit yoke, and the second yoke end width, defined by the radial width at both ends of the second unit yoke opposite to the first unit yoke, can be formed to be the same as each other. Thus, even if the first unit yoke is formed of a material with relatively low magnetic flux density, magnetic flux saturation occurring at the first unit yoke can be suppressed.

[0018] For example, the intermediate width of the first yoke, defined by the radial width of the first unit yoke at the intersection of the inner circumferential surface of the first unit yoke and the side surface of the first tooth, can be made larger than the intermediate width of the second yoke, defined by the radial width of the second unit yoke at the intersection of the inner circumferential surface of the second unit yoke and the side surface of the second tooth. This maximizes the slot area of ​​the second unit core, thereby increasing the coil wire diameter of the second stator coil relative to the same number of turns.

[0019] As another example, the first interior angle between the first unit yoke and the first tooth can be formed to be larger than the second interior angle between the second unit yoke and the second tooth. Therefore, by increasing the slot length of the second unit core, the slot area of ​​the second unit core can be ensured to be as wide as possible.

[0020] For example, the first interior angle can be formed as an obtuse angle, and the second interior angle can be formed as a right angle. This ensures that the slot area of ​​the second unit core is wider than the slot area of ​​the first unit core.

[0021] As another example, in the plurality of unit cores, the tooth widths of the teeth between unit cores made of different materials can be formed to be different. In the stator coils, the coil wire diameters of the stator coils wound around the unit cores with different tooth widths can be formed to be different. Therefore, with the same number of turns, copper losses at the stator coils can be minimized, thereby improving motor efficiency.

[0022] For example, the plurality of unit cores may include a first unit core and a second unit core. The second unit core may be configured to have a higher magnetic flux density than the first unit core. The wire diameter of the second stator coil wound around the second unit core may be configured to be larger than the wire diameter of the first stator coil wound around the first unit core. This allows for improved motor efficiency by minimizing copper losses at the second stator coil.

[0023] Specifically, insulators can be provided on both axial sides of the stator core. Each insulator can have a plurality of terminals, and at least one of these terminals can connect the first stator coil and the second stator coil to each other. Thus, even if the wire diameters of the first and second stator coils are different, the first and second stator coils can be smoothly connected.

[0024] Furthermore, the insulator may be provided with terminals, which connect the two ends of the connecting coil between the first stator coil and the second stator coil to the terminals of the first stator coil and the second stator coil, respectively. Thus, even if the wire diameters of the first stator coil and the second stator coil are different, the first stator coil and the second stator coil can be connected smoothly.

[0025] Furthermore, the wire diameter of the connecting coil can be made the same as that of the first stator coil. This minimizes copper losses at the connecting coil, thereby improving motor efficiency.

[0026] As another example, the first unit core can be formed from silicon steel sheet, and the second unit core can be formed from cobalt steel sheet. This allows for improved motor efficiency and reduces material costs.

[0027] In this case, the number of turns of the coil wound around the first unit iron core and the number of turns of the coil wound around the second unit iron core can be the same. This ensures motor efficiency and stability. Attached Figure Description

[0028] Figure 1 This is a perspective view showing the stator of this embodiment.

[0029] Figure 2 yes Figure 1 Top view of the stator.

[0030] Figure 3 This is a perspective view showing the stator core of this embodiment.

[0031] Figure 4 It is shown Figure 3 A top view of the stator core.

[0032] Figure 5 It is Figure 4 A magnified top view of a portion of the stator core.

[0033] Figure 6 This is a top view showing the stator core of this embodiment with coils wound around it, magnified and shown.

[0034] Figure 7 This is a perspective view showing the enlarged connection structure of the stator coils of the stator in this embodiment.

[0035] Figure 8 This is a schematic diagram shown to illustrate the connection state of the stator coils in this embodiment.

[0036] Figure 9 This is a table comparing and showing the efficiency and material costs of the first and second unit cores in the stator of this embodiment arranged in different ways. Detailed Implementation

[0037] The stator of the motor of the present invention will be described in detail below through the following embodiment.

[0038] Figure 1 This is a perspective view showing the stator of this embodiment. Figure 2 yes Figure 1 Top view of the stator.

[0039] Reference Figure 1 and Figure 2 The stator 100 of the motor in this embodiment may include a stator core 110, a stator coil 120, an insulator 130, and an insulating sheet 140. The stator core 110 is a component that forms a magnetic circuit, the stator coil 120 is a component that forms a magnetic circuit on the stator core 110, the insulator 130 is a component that insulates the axial side surface of the stator core 110, and the insulating sheet 140 is a component that insulates the inner circumferential surface of the stator core 110.

[0040] In the stator core 110, a plurality of unit cores 110a, which are composed of a plurality of steel plates stacked together, can be connected to each other to form a ring. In other words, in the stator core 110 that forms a segmented core, a plurality of unit cores 110a, which are composed of a plurality of steel plates stacked along the axial direction, can be assembled with different unit cores 110a that are adjacent in the circumferential direction to each other to form a ring.

[0041] In this case, among the plurality of unit cores 110a, unit cores 110a made of different materials, such as different magnetic flux densities, can be arranged alternately along the circumference. For example, the plurality of unit cores 110a can be formed from two types of unit cores 110a having different magnetic flux densities. The plurality of unit cores 110a formed of two different materials can be arranged in groups of several alternately along the circumference. For example, unit cores 110a formed of the same material can be arranged in groups of three alternately. Depending on the situation, the plurality of unit cores 110a can also have three or more types. In this embodiment, the description focuses on an example in which a plurality of unit cores 110a, 110a2 formed of two different materials are arranged alternately along the circumference.

[0042] Figure 3 This is a perspective view showing the stator core of this embodiment. Figure 4 It is shown Figure 3 A top view of the stator core. Figure 5 It is Figure 4 A magnified top view of a portion of the stator core. Figure 6 This is a top view showing the stator core of this embodiment with coils wound around it, magnified and shown.

[0043] Reference Figures 3 to 5 A plurality of unit cores 110a may be formed from a first unit core 111 having a first magnetic flux density and a second unit core 112 having a second magnetic flux density. The first unit core 111 may be formed from a material having a magnetic flux density relatively lower than that of the second unit core 112, for example, from silicon steel sheet, and the second unit core 112 may be formed from a material having a magnetic flux density relatively higher than that of the first unit core 111, for example, from cobalt steel sheet. Since the basic shapes of the first unit core 111 and the second unit core 112 are similar to each other, the following description of the common parts of the first unit core 111 and the second unit core 112 will focus on the first unit core 111, and the description of the second unit core 112 will be replaced by the description of the first unit core 111.

[0044] For reference, cobalt steel is primarily composed of iron (Fe) and cobalt (Co). Depending on the industrial application, the cobalt content ranges from 5% to 30%. Due to its high magnetic susceptibility and magnetic stability, it maintains its performance even at high temperatures. It is mainly used in high-performance magnets or electronic equipment. However, while cobalt steel outperforms silicon steel, it is relatively more expensive.

[0045] In this embodiment, the first unit core 111 may include a first unit yoke 111a, a first tooth 111b, a first shoe 111c, and a first groove 111d. The first unit yoke 111a, the first tooth 111b, and the first shoe 111c may be formed inside the first unit core 111, and the first groove 111d may be formed outside the first unit core 111 and together with the second groove 112d of the adjacent second unit core 112 to form a groove.

[0046] The first unit yoke 111a can be formed in an arc shape. For example, the outer peripheral surface 111a1 of the first unit yoke 111a can be formed in a concave-convex arc shape, and the inner peripheral surface 111a2 of the first unit yoke 111a and the circumferential side surface 111b1 of the first tooth 111b (described later) can form a straight surface that intersects at an obtuse angle. For example, the first unit yoke 111a can be formed such that the first interior angle θ1 between the inner peripheral surface 111a2 of the first unit yoke 111a and one side circumferential side surface 111b1 of the first tooth 111b forms an obtuse angle of approximately 100°. Thus, the first tooth length L11, defined by the radial length of the first tooth 111b (described later), can be formed to be smaller than the second tooth length L12, defined by the radial length of the second tooth 112b (described later).

[0047] Reference Figure 4 and Figure 5 In the first unit yoke 111a, its radial width can be formed almost identically along the circumferential direction, skipping the first tooth 111b described later. For example, in the first unit yoke 111a, the first yoke end width D11, defined by the radial width at both ends of the circumferential direction, can be formed to be the same as or almost the same as the first yoke middle width D12, defined by the radial width of the first unit yoke 111a at the intersection of the first unit yoke 111a and the first tooth 111b. Thus, even if the first unit core 111 is formed of a silicon steel sheet with a relatively low magnetic flux density, magnetic flux saturation between the first tooth 111b and the first unit yoke 111a can be suppressed.

[0048] In this case, the first yoke intermediate width D12 can be formed to be greater than the second yoke intermediate width D22 described later. In other words, the first yoke end width D11 can be formed to be the same as the second yoke end width D21 described later, and the first yoke intermediate width D12 can be formed to be greater than the second yoke intermediate width D22 described later. Thus, as described above, since the magnetic flux movement from the first tooth 111b to the first unit yoke 111a is smoother, magnetic flux saturation at the first unit yoke 111a can be suppressed.

[0049] Furthermore, in this case, the inner circumferential surface 111a2 of the first unit yoke 111a can be formed on the same circumference as the inner circumferential surface 112a2 of the second unit yoke 112a, which will be described later. In other words, the first yoke distance L21, defined as the distance from the center Oc of the stator core 110 to the inner circumferential surfaces 111a2 of the two ends of the first unit yoke 111a, can be formed to be the same as the second yoke distance L22, defined as the distance from the center Oc of the stator core 110 to the inner circumferential surfaces 112a2 of the two ends of the second unit yoke 112a, which will be described later. As a result, the fill rate of the stator coil 120 can be improved by maximizing the slot area of ​​the first slot 111d and / or the slot area of ​​the second slot 112d.

[0050] The first tooth 111b can be formed as a rectangle with the same width along its length. For example, the first tooth 111b can extend radially inward from the center of the inner circumferential surface 111a2 of the first unit yoke 111a. Thus, the first tooth width D31, defined by the width dimension between the two circumferential ends of the first tooth 111b, can be formed to be shorter than the length between the two ends of the first unit yoke 111a and form a first groove 111d between it and the adjacent second tooth 112b, the first groove 111d forming the coil winding space.

[0051] Reference Figure 4 and Figure 5 The first tooth 111b can be formed shorter than the second tooth 112b described later. In other words, the first tooth length L11, defined by the length from the inner circumferential surface 111b2 of the first tooth 111b to the inner circumferential surface 111a2 of the first unit yoke 111a, can be formed smaller than the second tooth length L12, defined by the length from the inner circumferential surface 112b2 of the second tooth 112b to the inner circumferential surface 112a2 of the second unit yoke 112a. Therefore, as described above, the first yoke end width D11 of the first unit yoke 111a can be formed to be the same as the first yoke end width D11 of the second unit yoke 112a, and the first yoke middle width D12 of the first unit yoke 111a can be formed to be the same as the first yoke end width D11. Thus, even if the first unit yoke 111a is formed of a material with a relatively low magnetic flux density, magnetic flux saturation at the first unit yoke 111a can be suppressed.

[0052] The first boot 111c can be formed in an arc shape. For example, the first boot 111c can extend circumferentially to both sides from the inner end of the first tooth 111b, and the circumferential length of the first boot 111c can be shorter than the circumferential length of the first unit yoke 111a. In other words, the first unit yoke 111a can contact the adjacent second unit yoke 112a, while the first boot 111c can be separated from the adjacent second boot 112c by a predetermined interval. Thus, the winding nozzle can enter and exit the inner circumference of the stator core 110, while the stator coil 120 can be wound around the first tooth 111b of the stator core 110.

[0053] The first slot 111d, serving as the space for winding the stator coil 120, can be formed by the inner circumferential surface 111a2 of the first unit yoke 111a, the circumferential side surface 111b1 of the first tooth 111b, and the outer circumferential surface 111c1 of the first shoe 111c. In other words, the first slot 111d can be formed on both circumferential sides, separated by the first tooth 111b. Thus, the first slot 111d of the first unit core 111 can form a single slot together with the second slot 112d of the circumferentially adjacent second unit core 112.

[0054] Reference Figures 3 to 5In this embodiment, the second unit core 112 may include a second unit yoke 112a, a second tooth 112b, a second shoe 112c, and a second groove 112d. As described above, the basic shape of the second unit core 112 may be the same as that of the first unit core 111. In other words, the second unit yoke 112a may be formed corresponding to the first unit yoke 111a, the second tooth 112b may be formed corresponding to the first tooth 111b, the second shoe 112c may be formed corresponding to the first shoe 111c, and the second groove 112d may be formed corresponding to the first groove 111d. Thus, the second unit yoke 112a, the second tooth 112b, and the second shoe 112c may be respectively disposed inside the second unit core 112, and the second groove 112d may be formed outside the second unit core 112 and together with the first groove 111d of the adjacent first unit core 111 to form a groove.

[0055] Reference Figure 4 and Figure 5 The second yoke 112a can be formed into an arc shape similar to the first yoke 111a. For example, the outer peripheral surface 112a1 of the second yoke 112a, like the outer peripheral surface 111a1 of the first yoke 111a, can be formed into a concave-convex arc shape, and the inner peripheral surface 112a2 of the second yoke 112a, like the inner peripheral surface 111a2 of the first yoke 111a, can be formed into a straight surface. Therefore, the arc length of the second yoke 112a can be the same as the arc length of the first yoke 111a.

[0056] In other words, the inner circumferential surface 112a2 of the second unit yoke 112a can be formed as a straight surface orthogonal to the circumferential side surface 112b1 of the second tooth 112b (described later). For example, the second unit yoke 112a can be formed such that the second interior angle θ2 between the inner circumferential surface 112a2 of the second unit yoke 112a and one side circumferential side surface 112b1 of the second tooth 112b forms a right angle. Therefore, the second tooth length L12, defined by the radial length of the second tooth 112b (described later), can be formed to be greater than the radial length of the first tooth 111b described above, that is, greater than the second tooth length L12. Consequently, the slot area of ​​the second slot 112d (described later) can be expanded to be greater than the slot area of ​​the first slot 111d, increasing the coil wire diameter of the stator core 110 relative to the same number of turns. In this way, magnetic flux saturation at the second stator coil 122 (described later) can be reduced, and correspondingly, copper losses at the stator coil 120 will also be reduced, thereby improving motor efficiency.

[0057] The second unit yoke 112a can be formed such that its radial width gradually increases circumferentially with respect to the second tooth 112b, which will be described later. For example, in the second unit yoke 112a, the second yoke end width D21, defined by the radial width at both ends in the circumferential direction, can be formed to be greater than the second yoke middle width D22, defined by the radial width of the second unit yoke 112a at the intersection of the second unit yoke 112a and the second tooth 112b. Thus, even if the middle portion of the second unit yoke 112a is formed to be narrower than the two ends, since the second unit yoke 112 is formed from a cobalt steel plate with a relatively high magnetic flux density, magnetic flux saturation between the second tooth 112b and the second unit yoke 112a can be suppressed.

[0058] In this case, the second yoke distance L22, defined as the distance from the center Oc of the stator core 110 to the inner circumferential surfaces 112a2 at both ends of the second unit yoke 112a, can be formed to be the same as the first yoke distance L21, defined as the distance from the center Oc of the stator core 110 to the inner circumferential surfaces 111a2 at both ends of the first unit yoke 111a. Thus, the outer circumferential surfaces 112a1 and 112a2 of the second unit yoke 112a can be located on the same circumference as the outer circumferential surfaces 111a1 and 111a2 of the first unit yoke 111a facing them. This effectively suppresses magnetic flux saturation between the first unit yoke 111a and the second unit yoke 112a, thereby preventing a decrease in motor efficiency.

[0059] The second tooth 112b, like the first tooth 111b, can be formed as a rectangle with the same width along its length. For example, the second tooth 112b can extend radially inward from the center of the inner circumferential surface 112a2 of the second unit yoke 112a. Thus, the second tooth width D32, defined by the width dimension between the two circumferential ends of the second tooth 112b, can be formed to be shorter than the length between the two ends of the second unit yoke 112a and form a second groove 112d between it and the adjacent first tooth 111b, the second groove 112d forming the coil winding space.

[0060] In this case, the second tooth width D32 can be made smaller than the first tooth width D31. In other words, since the second magnetic flux density of the second unit core 112 is higher than the first magnetic flux density of the first unit core 111, even if the second tooth 112b is made thinner than the first tooth 111b, the magnetic flux saturation at the second tooth 112b will not be greater than the magnetic flux saturation at the first tooth 111b. Therefore, the second tooth width D32 of the second unit core 112 can be made smaller than the first tooth width D31 of the first unit core 111. As a result, iron losses at the stator core 110 can be reduced by using cobalt steel plates with higher magnetic flux density, and the increase in material cost of the stator core 110 can be minimized by minimizing the amount of relatively expensive cobalt steel plates used.

[0061] Reference Figure 6 Since the second tooth width D32 of the second unit core 112 is smaller than the first tooth width D31 of the first unit core 111, the slot area of ​​the second slot 112d can be made wider than the slot area of ​​the first slot 111d. Therefore, when the number of turns of the first stator coil 121 wound around the first unit core 111 and the number of turns of the second stator coil 122 wound around the second unit core 112 are the same, the wire diameter D42 of the second stator coil 122 can be made larger than the wire diameter D1 of the first stator coil 121. This reduces copper losses at the second stator coil 122 and reduces overall copper losses at the stator coil, thereby improving motor efficiency. In other words, the number of turns of the first stator coil 121 and the number of turns of the second stator coil 122 can be the same, and the wire diameter D2 of the second stator coil 122 can be made thicker than the wire diameter D1 of the first stator coil 121.

[0062] Reference Figure 5 The second tooth 112b can be formed to be longer than the first tooth 111b described above. In other words, with the inner circumferential surface 112a2 of the second yoke 112a located on the same circumference as the inner circumferential surface 111a2 of the first yoke 111a, the inner circumferential surface 112a2 of the second yoke 112a can be formed to be orthogonal to the second tooth 112b. Therefore, the second tooth length L12, defined by the length from the inner circumferential surface 112b2 of the second tooth 112b to the inner circumferential surface 112a2 of the second yoke 112a, can be formed to be greater than the first tooth length L11, defined by the length from the inner circumferential surface 111b2 of the first tooth 111b to the inner circumferential surface 111a2 of the first yoke 111a. Therefore, as described above, the slot area of ​​the second slot 112d is increased to be larger than the slot area of ​​the first slot 111d. For the same number of turns, the wire diameter D42 of the second stator coil 122 (described later) can be increased to be larger than the wire diameter D41 of the first stator coil 121 (described later). In this way, magnetic flux saturation at the stator coil 120 can be suppressed, thereby correspondingly improving motor efficiency.

[0063] Reference Figures 3 to 5 In this embodiment, the second boot 112c, like the first boot 111c, can be formed in an arc shape. For example, the second boot 112c can extend circumferentially to both sides from the inner end of the second tooth 112b, and the circumferential length of the second boot 112c can be shorter than the circumferential length of the second unit yoke 112a. Thus, while the winding nozzle can enter and exit the inner circumference of the stator core 110, the stator coil 120 can be wound around the second tooth 112b of the stator core 110.

[0064] Reference Figures 3 to 5In this embodiment, the second slot 112d serves as a space for winding the stator coil 120 and can be formed by the inner circumferential surface 112a2 of the second unit yoke 112a, the circumferential side surface 112b1 of the second tooth 112b, and the outer circumferential surface 112c1 of the second shoe 112c. In other words, the second slot 112d is formed on both circumferential sides, separated by the second tooth 112b. Thus, as described above, the second slot 112d can form a slot together with the first slot 111d of the adjacent first unit core 111.

[0065] Reference Figure 1 and Figure 2 In this embodiment, the stator coil 120 can be wound around the first tooth 111b and the second tooth 112b of the stator core 110 and accommodated in the first slot 111d and the second slot 112d. For example, the stator coil 120 is formed by three phases such as U, V, and W, and the stator coil 120 of each phase can be formed by a first stator coil 121, a second stator coil 122, and a connecting coil 123, respectively. The first stator coil 121 is a coil wound around the first tooth 111b of the first unit core 111, the second stator coil 122 is a coil wound around the second tooth 112b of the second unit core 112, and the connecting coil 123 is a coil connecting the first stator coil 121 and the second stator coil 122.

[0066] In this case, the first stator coil 121, the second stator coil 122, and the connecting coil 123 in each phase of the stator coil 120 can be formed from the same material or from different materials. In the former case, the material cost and / or manufacturing cost of the stator coil 120 can be optimized; in the latter case, motor efficiency can be improved by minimizing copper losses at the stator coil 120. In this embodiment, an example is shown where the first stator coil 121, the second stator coil 122, and the connecting coil 123 in each phase are formed from the same material.

[0067] Furthermore, in this case, the first stator coil 121, the second stator coil 122, and the connecting coil 123 in each phase of the stator coil 120 can be formed with the same coil wire diameter, or they can be formed with different coil wire diameters. In the former case, the coil winding operation of the stator coil 120 is easier; in the latter case, motor efficiency can be improved by suppressing magnetic flux saturation at a portion of the coil (e.g., the second stator coil). In this embodiment, the latter case is shown, that is, an example is shown where the coil wire diameter D42 of the second stator coil 122 is formed to be larger than the coil wire diameter D41 of the first stator coil 121. In this case, the coil wire diameter D43 of the connecting coil 123 can be formed to be equal to or larger than the coil wire diameter D42 of the second stator coil 122. Thus, motor efficiency can be improved by suppressing magnetic flux saturation at the connecting coil 123.

[0068] The stator coil 120 is wound around its respective unit core by the winding nozzles of winders (not shown) arranged axially at predetermined intervals along the stacking direction of the stator core 110. Each winding nozzle simultaneously moves repeatedly in both horizontal and vertical directions, winding the stator coil 120 around its respective unit core. After winding the stator coil 120 around three unit cores, the winding nozzles move horizontally at three unit core intervals. Then, the winding nozzles are moved to their respective slots 111d and 112d, and the winding operation is repeated. Finally, with the stator coil 120 inserted into the three-phase positions at the neutral point, the coil is cut.

[0069] Subsequently, connecting coils 123 for each phase are used to connect the first stator coil 121 and the second stator coil 122 of each phase. At this time, the connecting coils 123 for each phase can be made of the same material and with the same wire diameter as the first stator coil 121 and / or the second stator coil 122 of each phase. For example, the connecting coil 123 for phase U can be made of the same material and with the same wire diameter as the relatively thicker second stator coil 122 for phase U. This reduces the material cost of the connecting coils 123 while minimizing copper losses at the connecting coils 123, thereby improving motor efficiency.

[0070] In this case, the two ends of the connecting coil 123 of each phase can be connected to the first stator coil 121 and the second stator coil 122 of each phase via their respective magnetic connectors 1316 at the terminals 1314 of the insulator 130 (described later). Thus, even if the first stator coils 121 and 122 of each phase have different wire diameters and are wound on different unit cores 111 and 112 respectively, the first stator coils 121 and 122 can be connected to each other via the connecting coil 123. The magnetic connector 1316 will be described again later along with the terminal 1314.

[0071] Reference Figure 1 and Figure 2 In this embodiment, the insulator 130 may include a first insulator 131 and a second insulator 132. The first insulator 131 is an insulator disposed on one side of the axial direction, and the second insulator 132 is an insulator disposed on the other side of the axial direction. Since the first insulator 131 and the second insulator 132 are formed to be almost identical, the following description will focus on the first insulator 131.

[0072] For example, the first insulator 131 can be formed to correspond to a plurality of unit cores 110a. In other words, the first insulator 131 can be separated into a number of unit cores 110a and formed independently in a single form, or it can be formed into a plurality of units and connected to each other according to the total number of unit cores 110a. In this embodiment, an example of the first insulator 131 being formed as a single unit is shown. Therefore, the following first insulator 131 and / or second insulator 132 can be understood as a single first insulator 131 and / or second insulator 132. Of course, depending on the circumstances, the first insulator 131 can also refer to the entire first insulator 131, and the second insulator 132 can also refer to the entire second insulator 132.

[0073] Specifically, the first insulator 131 may include a first yoke insulating portion 1311, a first tooth insulating portion 1312, a first shoe insulating portion 1313, and a terminal 1314. In other words, a single first insulator 131 may include the first yoke insulating portion 1311, the first tooth insulating portion 1312, the first shoe insulating portion 1313, and the terminal 1314, respectively. The first yoke insulating portion 1311 is the portion that insulates between the unit yokes 111a and 112a of the stator core 110 and the stator coil 120; the first tooth insulating portion 1312 is the portion that insulates between the teeth 111b and 112b of the stator core 110 and the stator coil 120; the first shoe insulating portion 1313 is the portion that insulates between the shoes 111c and 112c of the stator core 110 and the stator coil 120; and the terminal 1314 is the portion that connects the first stator coil 121 or the second stator coil 122 to the connecting coil 123.

[0074] The first yoke insulation portion 1311 can protrude along the axial direction at a predetermined height. Thus, the first yoke insulation portion 1311 can insulate the stator core 110 and the stator coil 120 while also insulating the stator coil 120 with the components surrounding it, such as the motor housing (not shown) and / or the compressor housing (not shown) that includes the motor.

[0075] The inner circumferential surface of the first yoke insulation portion 1311 can be formed as a straight surface to correspond to the inner circumferential surfaces 111a2 and 112a2 of the unit yokes 111a and 112a. As a result, the volume of the slots 111d and 112d of the stator core 110 can be ensured to be as wide as possible to improve the fill rate of the stator coil 120.

[0076] The first tooth insulation portion 1312 can be formed on the inner peripheral surface of the first yoke insulation portion 1311, extending along the inner side. A first coil winding groove (not shown) can be formed on the axial side away from the stator core 110. The first coil winding groove can be formed obliquely along the direction of winding the stator coil 120. As a result, when winding the stator coil 120, the alignment of the stator coil 120 can be improved, thereby suppressing the decrease in the fill rate of the stator coil 120.

[0077] Although not shown, a second coil winding slot (not shown) may be formed on the second insulator 132. The second coil winding slot may be formed in a direction that intersects with the first coil winding slot when projected axially, for example, in a direction orthogonal to the circumferential side of the first tooth insulation portion 1312. As a result, the alignment of the stator coil 120 can be improved when winding the stator coil 120.

[0078] The first boot insulation portion 1313 may extend circumferentially on both sides from the inner end of the first tooth insulation portion 1312. The first boot insulation portion 1313 may extend to the same length on both sides, or it may extend to different lengths. For example, the circumferential length of the first boot insulation portion 1313 may be the same as the circumferential length of the boot 111c, or the circumferential length of the first boot insulation portion 1313 may be longer than the circumferential length of the boot 111c. In the former case, the winding operation can be made easier by ensuring a wider spacing between adjacent first boot insulation portions 1313 on both sides to the maximum extent. In the latter case, the two ends of the first boot insulation portion 1313 may protrude more circumferentially relative to the two ends of the boot 111c and support the insulating sheet 140 described later in the axial direction.

[0079] As described above, terminals 1314 can be formed on individual first insulators 131 connected to their respective unit cores 111 and 112. As shown in this embodiment, since the stator coil 120 is formed by three phases U, V, and W, the terminals 1314 of each phase can also be arranged sequentially in the circumferential direction to connect the stator coils 120 of the three phases respectively. Since these terminals 1314 of each phase are formed identically to each other, the following description focuses on the terminal 1314 used to connect the stator coil of phase U.

[0080] Figure 7 This is a perspective view showing the enlarged connection structure of the stator coils in this embodiment. Figure 8 This is a schematic diagram shown to illustrate the connection state of the stator coils in this embodiment.

[0081] In this embodiment, the terminal 1314 can be formed on the first insulator 131, or on the second insulator 132, or on both the first insulator 131 and the second insulator 132. In this embodiment, an example is shown where the terminal 1314 is formed on the first insulator 131.

[0082] Reference Figure 7 and Figure 8 In this embodiment, terminal 1314 may include coil insertion slot 1315 and magnetic connector 1316. Coil insertion slot 1315 is the portion for inserting three-phase coils respectively, and magnetic connector 1316 is the portion for connecting the coils inserted into coil insertion slot 1315 to each other. Thus, coil insertion slot 1315 can extend integrally from the first insulator 131 and be formed of the same material as the first insulator 131, while magnetic connector 1316 can be formed of a different material than the first insulator 131, in other words, a conductor.

[0083] For example, two coil insertion slots 1315 can be formed in a single terminal 1314. In other words, the coil insertion slots 1315 can be circumferentially separated and formed as a first coil insertion slot 1315a and a second coil insertion slot 1315b. In this case, a first magnetic connector 1316a can be inserted into the first coil insertion slot 1315a, and a second magnetic connector 1316b can be inserted into the second coil insertion slot 1315b. The first coil insertion slot 1315a and the second coil insertion slot 1315b can be formed identically to each other, and the first magnetic connector 1316a and the second magnetic connector 1316b can also be formed identically to each other.

[0084] In the first coil insertion slot 1315a and the second coil insertion slot 1315b, the two coil slots 1315a1 and 1315a2 can be formed circumferentially separated by a predetermined interval. In other words, in the first coil insertion slot 1315a, the first coil slot 1315a1 and the second coil slot 1315a2 can be formed circumferentially, and in the second coil insertion slot 1315b, the third coil slot 1315b1 and the fourth coil slot 1315b2 can be formed circumferentially. The second coil slot 1315a2 and the third coil slot 1315b1 can be separated from each other by a partition wall. Thus, the first magnetic connector 1316a inserted in the first coil insertion slot 1315a and the second magnetic connector 1316b inserted in the second coil insertion slot 1315b can be separated from each other.

[0085] In this configuration, the second end of the first connecting coil 123a can be inserted into the first coil slot 1315a1, the first end (input end) of the first stator coil 121 can be inserted into the second coil slot 1315a2, the first end of the second connecting coil 123b can be inserted into the third coil slot 1315b1, and the second end (output end) of the first stator coil 121 can be inserted into the fourth coil slot 1315b2. The second end of the first connecting coil 123a and the first end of the first stator coil 121 can be connected to each other via a first magnetic connector 1316a inserted into the first coil insertion slot 1315a, and the first end of the second connecting coil 123b and the second end of the first stator coil 121 can be connected to each other via a second magnetic connector 1316b inserted into the second coil insertion slot 1315b. By repeatedly connecting in the manner described above, the first stator coil 121 can be electrically connected to the adjacent second stator coil 122 via the first connecting coil 123a and the second connecting coil 123b.

[0086] Although not illustrated, in addition to the connecting coil 123 of the above embodiment, the first stator coil 121 and the second stator coil 122 can be connected to each other at their respective terminals 1314. For example, after the first stator coil 121 of the U phase is wound around the first unit core 111 of the U phase, it is inserted into the first coil insertion slot 1315a of the terminal 1314 located above or below the second unit core 112 of the U phase, spanning the adjacent first unit cores 111 of the V and W phases. After the second stator coil 122 of the U phase is wound around the second unit core 112, it is inserted into the second coil insertion slot 1315b of the terminal 1314. Then, the first stator coil 121 and the second stator coil 122 of the U phase can be connected to each other by inserting the magnetic connector 1316 into the corresponding terminal 1314. The stator coils of the V phase and the stator coils of the W phase can also be connected in the same manner.

[0087] In this way, the first unit core 111 and the second unit core 112 forming the stator core 110 can be formed from different materials. In other words, the first unit core 111 of each phase can be formed from silicon steel sheet, while the second unit core 112 of each phase can be formed from cobalt steel sheet with a higher magnetic flux density than silicon steel sheet. As described above, the yoke width and / or tooth width of the second unit core 112 can be made smaller than the yoke width and / or tooth width of the first unit core 111. Therefore, iron loss can be reduced by using cobalt steel sheet with a higher magnetic flux density, and the increase in material cost can be minimized by minimizing the amount of relatively expensive cobalt steel sheet used.

[0088] Furthermore, when the number of turns of the first stator coil 121 wound on the first unit core 111 and the second stator coil 122 wound on the second unit core 112 are the same, the wire diameter of the second stator coil 122 can be made larger than that of the first stator coil 121. Thus, by using cobalt steel plates to reduce iron losses at the stator core 110, the overall motor efficiency can be improved by reducing copper losses at the stator coil 120.

[0089] Although not illustrated, the first unit core 111 and the second unit core 112 can be combined in various ways depending on the design purpose. For example, in the aforementioned embodiment, the number of second unit cores 112 formed from cobalt steel plates in the stator core 110 can be configured to be the same as the number of first unit cores 111 formed from silicon steel plates. Alternatively, depending on the situation, the number of second unit cores 112 can be less than the number of first unit cores 111, or the number of second unit cores 112 can be greater than the number of first unit cores 111. Even in these cases, as described above, it is possible to minimize the increase in material costs and improve motor efficiency.

[0090] Figure 9 This is a table comparing and showing the efficiency and material costs of the first and second unit cores in the stator of this embodiment arranged in different ways.

[0091] Reference Figure 9 Example 1 is an example where the entire unit core 110a is formed solely from the first unit core 111 of silicon steel plate; Example 2 is an example where the first unit core 111 of silicon steel plate is three times the size of the second unit core 112 of cobalt steel plate; Example 3 is an example where the first unit core 111 and the second unit core 112 are formed in the same quantity; Example 4 is an example where the second unit core 112 is three times the size of the first unit core 111; and Example 5 is an example where the entire unit core 110a is formed solely from the second unit core 112 of cobalt steel plate.

[0092] In this case, from the perspective of motor efficiency, it can be confirmed that the motor efficiency, which is the value obtained by dividing the output (including iron loss and copper loss) by the input, is 89.9% in the case of Example 1, and has the highest rate of increase in the cases of Example 3 and Example 4. That is, the motor efficiency of Example 3 is improved by 0.7% compared to Example 2, and the motor efficiency of Example 4 is improved by 0.7% compared to Example 3.

[0093] Regarding the material cost of the stator core, it can be confirmed that, with the same material cost for the rotor and magnet, the material cost of the stator core 110 gradually increases as more cobalt steel plates are used in Example 5. As in Example 5, the width of the stator core gradually decreases, and correspondingly, the wire diameter of the stator coil 120 gradually increases, thus increasing the material cost of the coil accordingly. That is, it can be confirmed that, from Examples 1 to 5, the three major material costs—the material cost of the stator and rotor core, the material cost of the magnet, and the material cost of the stator coil 120—gradually increase. However, in terms of relative growth rate, Example 3 shows the largest increase, at 22.5%. This confirms that, as the coil wire diameter increases, as shown in the motor efficiency example above, copper losses decrease, and motor efficiency significantly improves. Therefore, the stator core 110 can be appropriately combined with the first unit core 111 and the second unit core 112 in various examples as described above, according to the design purpose.

Claims

1. A stator for a motor, wherein, include: The stator core consists of multiple unit cores connected together to form a ring; as well as Stator coils are wound around a plurality of the aforementioned unit iron cores; Each of the aforementioned unit cores is formed of a material with a different magnetic flux density.

2. The stator of the motor according to claim 1, wherein, The plurality of said unit cores includes: The first unit core has a first magnetic flux density; and The second unit core has a second magnetic flux density that is higher than that of the first magnetic flux density.

3. The stator of the motor according to claim 2, wherein, The first unit core and the second unit core are arranged alternately in the circumferential direction.

4. The stator of the motor according to claim 2, wherein, The first unit core includes a first unit yoke and a first tooth extending from the first unit yoke; The second unit core includes a second unit yoke and a second tooth extending from the second unit yoke; The width of the second tooth, defined by the width dimension between the two circumferential ends of the second tooth, is formed to be smaller than the width of the first tooth, defined by the width dimension between the two circumferential ends of the first tooth.

5. The stator of the motor according to claim 4, wherein, The first yoke distance, defined as the distance from the center of the stator core to the inner circumferential surfaces of the two ends of the first unit yoke, is formed to be the same as the second yoke distance, defined as the distance from the center of the stator core to the inner circumferential surfaces of the two ends of the second unit yoke.

6. The stator of the motor according to claim 5, wherein, The first tooth length, defined by the length from the inner circumferential surface of the first tooth to the inner circumferential surface of the first unit yoke, is formed to be less than the second tooth length, defined by the length from the inner circumferential surface of the second tooth to the inner circumferential surface of the second unit yoke.

7. The stator of the motor according to claim 4, wherein, The first yoke end width, defined by the radial width of the two ends of the first yoke, and the second yoke end width, defined by the radial width of the two ends of the second yoke opposite to the first yoke, are formed to be the same as each other.

8. The stator of the motor according to claim 7, wherein, The first yoke intermediate width, defined by the radial width of the first yoke at the intersection of the inner circumferential surface of the first yoke and the side surface of the first tooth, is formed to be greater than the second yoke intermediate width defined by the radial width of the second yoke at the intersection of the inner circumferential surface of the second yoke and the side surface of the second tooth.

9. The stator of the motor according to claim 4, wherein, The first interior angle between the first unit yoke and the first tooth is formed to be greater than the second interior angle between the second unit yoke and the second tooth.

10. The stator of the motor according to claim 9, wherein, The first interior angle is an obtuse angle, and the second interior angle is a right angle.

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